# 整数和字符串都是不可变，意味可以用来共享
# 不可变对象
a = 5
b = 5
c = a
print(a is b)
print(c is a)

s1 = 'python'
s2 = 'python'
print(s1 is s2)

# 可变对象
list1 = ['a', 'b', 'c']
list2 = ['a', 'b', 'c']
print(list1 is list2)
print(list1 is not list2)
